No it's not.
Ukrainian troops' qualification levels are dropping and they have manpower shortages. You can train a man in realistic time during war (if you have competent men free to do that, and not fighting), but you can't grow a baby into a man and then train him in realistic time during war.
Mercenaries are not a complete replacement.
I mean, for an ex-Soviet army they've shown class (and by the way, nothing in that was about inferiority of Soviet doctrine or something, just using it right). But they can't fight a trice stronger adversary with more than trice stronger economy on their own territory (which means that their own economy is half-dead), without some other component, and the amount of Western help right now is just not sufficient.